Abstract

Consideration of product volatility and thermodynamic stability have been central to models developed for the thermal etching and deposition of GaAs by Cl₂^1,2 Mass spectrometric studies of the etching chemistry have tended to support some of the basic assumptions of these models: that the thermodynamically most stable product is formed and that product volatility controls the etch rate. Surface analyses, for example, have revealed the presence of a Ga-rich scale after etching, to be expected if the As chlorides arc more volatile and desorb more readily.^3-5 Consequently, models of beam modification of GaAs in the presence of Cl₂ have focussed on how energetic particles or light might perturb the thermal reaction. In this work the validity of the basis for these models has been examined by investigation of the etching chemistry of doped GaAs by molecular beam mass spectrometry and in situ Auger spectroscopy.

© 1991 Optical Society of America